Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 10 6 2019 02 10 409 416 EN Maryam Kaihanfar Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Iran AND Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran Madjid Momeni-Moghaddam Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Iran Mohammad Javad Mehdipour Moghaddam Department of Biology, Faculty of Sciences, University of Guilan, Rasht, Iran Toktam Hajar Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Iran Vahab Dast Pak Pharmaceutical Technology Development Center, Jundishapur University of Medical Sciences, Ahvaz, Iran Jalal Omrani Bidi Department of Biology, Faculty of Sciences, Hakim Sabzevari University, Sabzevar, Iran 2018 08 11 2018 12 01 Background and Objectives: Larval therapy refers to the use of Lucilia sericata larvae on chronic wounds, which is a successful method of chronic wounds treatment. The secretions of these larvae contain antibacterial compounds and lead to death or inhibition of bacterial growth. Materials and Methods: In this study, we investigated the antibacterial effects of Lucilia sericata larvae secretions which were in sterilized and multi antibiotic-resistant bacteria-treated forms on Gram-positive Bacillus subtilis bacteria and Gram-negative Escherichia coli bacteria. In the following, we evaluated changes in gene expression of lucifensin and attacin during treatment with multi antibiotic-resistant bacteria. Investigation of the antibacterial effect was carried out using optical absorption and antibiotic disk diffusion in order to study the expression of the aforementioned genes. Results: The results of this study showed that E. coli-treated larvae were able to inhibit the growth of E. coli and secretions of B. subtilis-treated larvae and were also able to inhibit the growth of B. subtilis. Gene expression of antibacterial peptides in multi antibiotic-resistant bacteria-treated larvae was increased in comparison to non-treated larvae. Conclusion: Due to the significant antibacterial potency of bacteria-treated larvae secretions, the secretions can be a suitable candidate as a drug against antibiotic resistant bacteria, but additional tests are required. Since the antimicrobial peptides of insects have not yet produced any resistance in human pathogenic bacteria, they can be considered as a promising strategy for dealing with resistant infections. https://ijm.tums.ac.ir/index.php/ijm/article/view/1865 https://ijm.tums.ac.ir/index.php/ijm/article/download/1865/1089